HomeAway Inc. has escalated from small start up to top player in the online vacation rental industry, connecting travelers looking for a place to stay with hosts lending out their houses, apartments and condos around the world.

Listing more than 773,000 properties in 171 countries, the company says it relies on one unifying, global emblem for its businesses and services: a birdhouse. The logo has been copyrighted, and a two-story, 3-D replica of the symbol sits in its downtown Austin headquarters, enclosed behind glass windows that overlook West Fifth Street and Lamar Boulevard.

But in a lawsuit filed this week [embedded below] in federal court, HomeAway is alleging that it has entertained a bad guest. [See also why the suit is a turning point.]

The company is suing competitor Airbnb Inc. for trademark infringement, unfair competition and unjust enrichment, saying Airbnb CEO Brian Chesky has visited HomeAway’s Austin offices several times and borrowed heavily from its “Birdhouse Mark” for the first national campaign of his San Francisco-based business.

The $2 million advertising campaign, dubbed “Home to You,” launched Dec. 16 and features what the startup describes as a documentary-style film, capturing artists re-creating 50 of the most interesting and architecturally inspiring Airbnb properties as intricate miniature birdhouses.

Representatives of the California startup say the commercial — “Every Traveler Deserves a Home” — is meant to showcase craftsmanship and the unique array of listings available on Airbnb. But HomeAway is calling it “a blatant and intentional infringement and dilution of HomeAway’s Birdhouse Mark, causing incalculable damage to HomeAway’s goodwill,” according to records filed Tuesday in the Austin division of the U.S. Western District of Texas.

HomeAway CEO and Chairman Brian Sharples said Thursday that his company has an obligation to its shareholders to protect its trademark.

“We do believe it is a fairly deliberate attempt to confuse the marketplace,” Sharples said. Chesky “has been to our downtown offices several times. He has stepped into our giant birdhouse. I don’t think that anyone could argue that this was a mistake on their part.”

HomeAway, which was founded with six employees in 2005, has become a leading network of online vacation rentals through the acquisitions of smaller sites, such as Escapia.com and Toprural. It has now diversified into vacation home sales as well as rentals and boasts nearly 1,500 employees around the world and increasing revenue — more than $280 million last year, according to court records.

Embedded in the culture of the company, Sharples said, is the birdhouse logo, designed by downtown Austin advertising firm McGarrah Jessee and chosen “because it symbolizes what we do.”

The lawsuit says the trademark is used on several of the dozens of HomeAway websites, promotional activities and television commercials, including two Super Bowl ads in 2010 and 2011. The complaint includes photographs of the birdhouses that deck the walls of the first and fourth floors of its downtown Austin offices.

Every year, HomeAway officials said, new employees are invited to paint and decorate their own miniature birdhouse in a competition for the most creative. HomeAway is not seeking monetary compensation but wants the court to order Airbnb to stop using birdhouses or birdhouse themes in its campaigns and to destroy any products or ads embodying the Birdhouse Mark, the lawsuit says.

Chesky saw those displays when he received a personal tour of the facility in 2011, and he stood inside the replica the size of a child playhouse, the records allege.

Airbnb officials declined to comment on the allegations. But in a statement, they said their “Home to You” campaign, hosted out of birdbnb.com, “was designed to convey the creative and individual hospitality that Airbnb and its hosts celebrate every day.”

“‘Every Traveler Deserves a Home’ expresses our love for the real travelers of the world,” it said. The birdhouses in the video now hang in Audubon Park in New Orleans.

The San Francisco-based company, which operates out of a single website it launched in 2008, has emerged as a hefty competitor in the past five years — all through word of mouth, social media networks and limited ad campaigns. It, too, has grown into an international service with more than 550,000 listings.

Though the company has had targeted advertising campaigns in Los Angeles and at the Sundance Film Festival in Utah, Birdbnb was its first national effort.

“We promise you’ll never look at birdhouses the same way — and if you stay in one of these remarkable homes around the world, you may never look at travel the same way again too,” the website states.